<!DOCTYPE html>
<title>CSS Position Test: ::backdrop inherits from originating element - computed values</title>
<link rel="help" href="https://drafts.csswg.org/css-position-4/#backdrop">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  dialog {
    --foo: bar;
    --bg: green;
    left: 100px;
    color-scheme: dark;
  }
  dialog::backdrop {
    background-color: var(--bg);
    left: inherit;
  }
</style>
<dialog></dialog>
<script>
  let dialog = document.querySelector("dialog");
  setup(() => {
    dialog.showModal();
  });

  test(() => {
    let style = getComputedStyle(dialog, "::backdrop");
    assert_equals(style.getPropertyValue("--foo"), "bar");
    assert_equals(style.getPropertyValue("--bg"), "green");
  }, "Inherit custom property");

  test(() => {
    assert_equals(getComputedStyle(dialog, "::backdrop").backgroundColor, "rgb(0, 128, 0)");
  }, "Apply inherited custom property to background-color");

  test(() => {
    assert_equals(getComputedStyle(dialog, "::backdrop").colorScheme, "dark");
  }, "Implicitly inherited color-scheme");

  test(() => {
    assert_equals(getComputedStyle(dialog, "::backdrop").left, "100px");
  }, "Explicitly inherited left");
</script>
